PurposeThe purpose of this work is to explore electrical properties of an electrochemical sensor designed for the detection of malachite green (MG) present in an aqueous solution.Design/methodology/approachThe present sensor consists in the spatial coupling of a polymeric membrane and an ion-sensitive electrode (platinum electrode). The preparation of the polymeric membrane involves the incorporation of an ionophore (D2HPA), a polymer (polyvinylchloride [PVC]) and a plasticizer (dioctyl phthalate [DOP]). Several techniques have been used to characterize this sensor: the cyclic voltammetry, the electrochemical impedance spectroscopy and the optical microscopy. The sensibility, the selectivity and the kinetic study of a modified platinum electrode have been evaluated by cyclic voltammetry.FindingsThe obtained results reveal the possibility of a linear relationship between the current of reduction peaks and MG concentration. A linear response was obtained in a wide-concentration range that stretches from 10−5to 10−13mol L−1, with a good correlation coefficient (0.976) and a good detection limit of 5.74 × 10−14mol L−1(a signal-to-noise ratio of 3). In addition, the voltammetric response of modified electrode can be enhanced by adding a layer of Nafion membrane. Under this optimal condition, a linear relationship was obtained, with a correlation coefficient of 0.986 and a detection limit of 1.92 × 10−18mol L−1.Originality/valueIn the present research, a convenient, inexpensive and reproducible method for the detection of MG was developed. The developed sensor is capable of competing against the conventional techniques in terms of speed, stability and economy.
